4 wire O2 sensors

Post by **Legacy777** » Sun Jul 20, 2003 5:28 pm

Well with the talk about grounding mods and O2 sensors and all that stuff. I got to thinking, did some research and thought, why couldn't we just get a generic 4-wire O2 sensor, splice it into the existing harness that plugs into the car's harness, then take the O2 ground wire and tie it into a good chassis ground, or run it back to an ECU ground point.

Thoughts?

vrg3 · Post by **vrg3** » Sun Jul 20, 2003 11:28 pm

That'd work just fine. Running the ground to another sensor ground would probably be simplest.

Post by **Legacy777** » Mon Jul 21, 2003 4:30 pm

Where's the cheap place to get generic O2 sensors, is it just oxygensensors.com?

vrg3 · Post by **vrg3** » Mon Jul 21, 2003 5:33 pm

Yeah, oxygensensors.com is probably the cheapest place. They sell Walker sensors. The two relevant Walker part numbers are 250-24200 and 250-24000. The former costs about 10 bucks more. The difference is that it has an "isolated ground." I don't know exactly what that means, but I guess it just keeps the sensor and heater grounds completely separate. That might be better; I don't know. I guess it's possible that the non-isolated-ground version isn't actually a 4-wire sensor but just a 3-wire sensor with two wires going to the ground or some other similar cheat. I have no idea.

I think I'd go with the isolated ground version. That would be a universal sensor meant to replace the rear sensor on a 2002 Acura 3.2CL.

Post by **Legacy777** » Mon Jul 21, 2003 7:27 pm

Are all the sensors pretty much the same?

That acura 4-wire isolated ground was the only one I saw like that. I'd have to figure out which wire was which too....

vrg3 · Post by **vrg3** » Mon Jul 21, 2003 9:36 pm

Legacy777 wrote:Are all the sensors pretty much the same?

I'm not sure exactly what you mean here, but... all lambda sensors have pretty much the same construction and give pretty much the same readings. I'm pretty sure they all have M18x1.5 threads, too. The only differences are grounding and heating.

Oxygen sensors need to be warmed up to work correctly. Exhaust heat can do the job pretty well, but putting a heating element in the sensor makes sure it gets hot fast and stays hot.

So from what I can gather, there are these types of sensors:

1-wire: Has 1 wire for signal, grounds through its body.
2-wire: Has 1 wire for signal and 1 wire for signal ground. Unheated, just like 1-wire, but provides a clearer and more consistent signal.
3-wire: Has 1 wire for signal, and 2 wires for the heater. This is essentially a 1-wire sensor plus a heating element. Typically the heater wires are not polarity sensitive and are completely independent of the signal. The car itself will typically have one of the heater wires connected to ground and one to +12v. This is what our cars use.
4-wire: Has 1 wire for signal, 1 wire for signal ground, and 2 wires for the heater. This is essentially a 3-wire sensor with an additional ground for the signal. Just like the 3-wire sensor, typically the heater is completely independent of the signal and has no polarity and is usually connected with one side to ground and one side to +12v.

As I said before, the whole "isolated ground" issue kind of threw me for a loop... From what I understand, though, all proper 2-wire and 4-wire sensors have isolated ground, meaning that the ground line for the signal is not connected to the body of the sensor. It also seems that many aftermarket oxygen sensor manufacturers cheat a little. Basically, they take a 1-wire or 3-wire sensor and add an extra ground wire going to the sensor's body. They then sell it as a 2-wire or 4-wire sensor. Technically this is not correct, but should work fine. In my opinion, it can't hurt to get a proper 4-wire sensor for 10 bucks more.

As for figuring out which wire is which, usually aftermarket sensors use white wires for the heater (since it's not polarized both wires have the same color), a gray wire for signal ground, and a black wire for the signal.

All Honda/Acura 4-wire sensors should use isolated grounds. But you should be able to call up oxygensensors.com and ask them for a universal 4-wire isolated ground sensor. They'll probably give you the Walker 250-24200.

vrg3 · Post by **vrg3** » Mon Jul 21, 2003 9:39 pm

Oh, and one other thing I forgot to mention -- when cold, the heater can draw several amperes of current. The heater is self-regulating, so when it warms up it will draw much less current. So, when doing the wiring, be aware that the heater lines will carry that much current.

Post by **Legacy777** » Tue Jul 22, 2003 1:29 am

I emailed them and here's what I found out.

Hi,

I had a quick question for you. I have a 1990 Subaru legacy 2.2 liter. I currently have an OEM 3 wire O2 sensor. I would like to try and find a generic 4-wire O2 sensor that is compatible. I would then splice in the factory harness for the existing three wires and run an additional wire for the actual sensor ground.

I'm looking to do this since my car is aging and the grounding capability through the exhaust is probably not the best.

Do you have anything you can recommend?

Thanks

Josh,

Yes, our four wire universal would probably work for you. Part # 250-24000, $49.95 each. Here's a picture for reference:

http://www.oxygensensors.com/showpictur ... =250-24000

Mike Carter

Mike,

Thanks for the reply. I do have one further question. What would be the difference between the sensor you have listed below and the Walker 4-wire (isolated ground) sensor, # 250-24200?

Josh

Josh,

The 24200 has a different heater style than the 24000. The heater from your original three wire will more closely match that of our 24000...

Mike Carter

So it looks like the cheaper one would be the correct one to go with.

vrg3 · Post by **vrg3** » Tue Jul 22, 2003 3:58 am

Hmm... I was not aware that there were different types of heaters. In fact, I was pretty sure there weren't different types (among narrow-band sensors). I'd be interested in learning more about the difference, and also about why oxygensensors.com lists the difference between the two sensors as "isolated ground." But I suppose if they recommend the cheaper one, you can be pretty confident in it.

Cool.

Post by **Legacy777** » Tue Jul 22, 2003 2:02 pm

Yeah.....don't know why....4-wire is a 4-wire i guess....

ciper · Post by **ciper** » Fri Jul 25, 2003 7:11 pm

Im going to buy one, to be used with my new turbo engine. Most likely one of you will install it before me but if not Ill let you know how it works

250-24000

edit: Okay, either its just me or that site sucks when searching for the universal items!!

To order the part mention in this thread just look up the 1998 Ford Pickup (F Series) V8-4.6L and choose the one labeled "Universal 4 Walker $49.95 250-24000"

Post by **Legacy777** » Fri Jul 25, 2003 7:59 pm

Cool,

Thanks for the search tip. I agree their search function is a little lacking.

I'll be giving this guy a shot too, not sure when though. Depends on when i get moved in. But definitely post results when you get it in. I'll do likewise.

On a side note, I think turbo cars would provide more ground places for the exhaust then a n/a engine since the turbo is in the loop.

-K- · Post by **-K-** » Wed Sep 24, 2003 1:49 am

Ok, time for a O2 sensor. I might as well jump on this idea. My problem is that I want to find the pins that go in the stock clip so I don't have to splice any wires. If anybody has an idea where I can get them it would be great because all I can find are Ford and Chevy.
Second, if I'm going to run the sensor ground into the harness ground isn't that the same as the heater ground. The heater ground wire goes into the harness ground so can I just connect them? (heater and sensor ground)

vrg3 · Post by **vrg3** » Wed Sep 24, 2003 2:17 am

If I'm not mistaken, these connectors are made by Sumitomo, and it's nearly impossible for an ordinary mortal like you or me to get them.

You don't have to cut any of your car's wiring, though... Just cannibalize your old sensor (which you're getting rid of anyway) for the connector that'll go into your stock wiring.

The oxygen sensor heater ground is connected to the ECU's power supply ground, not its sensor ground, but the two are internally connected in the ECU, so... Yeah, go ahead and use the heater ground. It'll be convenient and it does actually connect to the ECU through wires (as opposed to through the chassis).

-K- · Post by **-K-** » Wed Sep 24, 2003 3:08 am

Yes I could use the stock clip, but I would have to connect it to the O2 sensor. I don't want to solder that close to the exhaust and don't know if butt connectors would hold up to the heat. I don't need the whole clip just the pins in it that I could crimp the wires into. Thanks and I'll see what I do whith that info.

123c · Post by **123c** » Tue Nov 18, 2003 4:38 am

ciper wrote: just me or that site sucks when searching for the universal items!!

To order the part mention in this thread just look up the 1998 Ford Pickup (F Series) V8-4.6L and choose the one labeled "Universal 4 Walker $49.95 250-24000"

When I looked the the 1998 Ford Pickup, it showed part 250-24400, I think I will email them, or try one of my local parts stores...

Post by **Legacy777** » Tue Nov 18, 2003 5:13 am

I emailed them to confirm which generic would work with my car. he recommended me the one I picked because its heater setup would be most like the OEM one.

123c · Post by **123c** » Tue Nov 25, 2003 4:36 am

I just emailed them, but they didn't help me much on how to order the 250-24000 online, so I guess I will have to end up calling them, and ordering it that way...

123c · Post by **123c** » Tue Nov 25, 2003 4:41 am

Ok, I just tried some combinations, and found that a 1999 Corvette uses the 250-24000...

Post by **Legacy777** » Tue Nov 25, 2003 4:05 pm

I used a 2002 Acura as my car to get the proper 4-wire....hehe

123c · Post by **123c** » Tue Nov 25, 2003 6:38 pm

Legacy777 wrote:I used a 2002 Acura as my car to get the proper 4-wire....hehe

I thought that the 250-24000 was the better choice than the 250-24200. I hope the 250-24000 will work out...

Post by **Legacy777** » Tue Nov 25, 2003 10:51 pm

I thought the acura used the 250-24000 ?

either way....the 250-24000 is the one I installed.

yup....this is what I ordered...

Oxygen Sensors:
Part number: 250-24000 Quantity: 1
2002 Acura CL V6-3.2L

georryan · Post by **georryan** » Sun Mar 14, 2004 10:51 pm

When I look up the 2002 Acura CL 3.2L it is a 250-24200, so I ordered for a corvette. The 250-24000 should be shipped soon. $50.35 after tax.

-Ryan

NICO · Post by **NICO** » Wed Mar 17, 2004 9:16 pm

does bosch make this 4 wire sensore

Post by **Legacy777** » Wed Mar 17, 2004 9:26 pm

I'm sure they make a 4-wire sensor...the one I used is a walker unit

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